Rockslide Monitoring Through Multi-temporal LiDAR DEM and TLS Data Analysis

The Mont de La Saxe rockslide (Courmayeur, Aosta Valley, Italy) is presently one of the most hazardous landslides in Northern Italy. Due to increasing activity in the last 5 years, the rockslide has been extensively investigated and monitored. We present topographic monitoring through ALS-LiDAR and TLS (Terrestrial Laser Scanning) surveys. This analysis is performed by visual comparison of LiDAR DEMs (1) in map and (2) profile format, and by the (3) elevation difference between successive DEMs. The efficacy of these three strategies depends on the rockslide kinematic, and the prevalence of either horizontal or vertical movements. In the first case, the visual comparison in map can be effective, while elevation difference is optimal to recognize prevalently vertical movements and areal extent of more active areas as well for a global zonation of the instability.